Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou 310027, People's Republic of China.
Gansu Provincial Key Laboratory of Wearable Computing, School of Information Science and Engineering, Lanzhou University, Lanzhou 730000, People's Republic of China.
J Neurosci. 2023 Jan 25;43(4):559-570. doi: 10.1523/JNEUROSCI.0874-22.2022. Epub 2022 Dec 5.
Thalamus is a critical component of the limbic system that is extensively involved in both basic and high-order brain functions. However, how the thalamic structure and function develops at macroscopic and microscopic scales during the perinatal period development is not yet well characterized. Here, we used multishell high-angular resolution diffusion MRI of 144 preterm-born and full-term infants in both sexes scanned at 32-44 postmenstrual weeks (PMWs) from the Developing Human Connectome Project database to investigate the thalamic development in morphology, microstructure, associated connectivity, and subnucleus division. We found evident anatomic expansion and linear increases of fiber integrity in the lateral side of thalamus compared with the medial part. The tractography results indicated that thalamic connection to the frontal cortex developed later than the other thalamocortical connections (parieto-occipital, motor, somatosensory, and temporal). Using a connectivity-based segmentation strategy, we revealed that functional partitions of thalamic subdivisions were formed at 32 PMWs or earlier, and the partition developed toward the adult pattern in a lateral-to-medial pattern. Collectively, these findings revealed faster development of the lateral thalamus than the central part as well as a posterior-to-anterior developmental gradient of thalamocortical connectivity from the third trimester to early infancy. This is the first study that characterizes the spatiotemporal developmental pattern of thalamus during the third trimester to early infancy. We found that thalamus develops in a lateral-to-medial pattern for both thalamic microstructures and subdivisions; and thalamocortical connectivity develops in a posterior-to-anterior gradient that thalamofrontal connectivity appears later than the other thalamocortical connections. These findings may enrich our understanding of the developmental principles of thalamus and provide references for the atypical brain growth in neurodevelopmental disorders.
丘脑是边缘系统的关键组成部分，广泛参与大脑的基本和高级功能。然而，在围产期发育过程中，丘脑在宏观和微观尺度上的结构和功能如何发育尚不清楚。在这里，我们使用多壳高角度分辨率扩散 MRI 对来自发育人类连接组计划数据库的 144 名男性和女性早产儿和足月儿进行了扫描，这些婴儿在 32-44 个月经周期后进行了扫描，以研究丘脑在形态、微观结构、相关连接和亚核分裂方面的发育情况。我们发现，与内侧部分相比，丘脑外侧的解剖扩张和纤维完整性的线性增加更为明显。轨迹结果表明，丘脑与额叶的连接发育晚于其他丘脑皮质连接（顶枕、运动、体感和颞叶）。使用基于连接的分割策略，我们揭示了丘脑亚核的功能分区在 32 个月经周期或更早时形成，并且分区以从外侧到内侧的模式向成人模式发展。总的来说，这些发现表明，外侧丘脑的发育速度比中央部分快，并且从第三个三个月到婴儿早期，丘脑皮质连接的发育呈现出从后向前的梯度。这是第一项描述第三个三个月到婴儿早期丘脑时空发育模式的研究。我们发现，丘脑的微观结构和亚核都以从外侧到内侧的模式发育；并且丘脑皮质连接呈现出从后向前的梯度，丘脑额叶连接的出现晚于其他丘脑皮质连接。这些发现可能丰富我们对丘脑发育原则的理解，并为神经发育障碍中异常大脑生长提供参考。
